Plastic ribbon spool

ABSTRACT

Plastic ribbon spools in which a tab, foldable from a spool flange, is adapted to pinch and secure one end of an inked ribbon to the spool core and lock in place with the ribbon so secured.

United States atent 3,622fi99 [72] Inventor John H. Bishop [50] Field of Search 242/74 Montreal, Quebec, Canada 74.]. 74.2; 197/175 21 1 Appl. No. 835,107

[22] Filed June 20, 1969 References Cited 45) Patented Nov. 23, 1971 UNITED STATES PATENTS I 1 Assignee 2- olivelti and -11.11. 793,672 7/1905 Lyter 242/741 lvrea, Italy 3,195,828 7/1965 Kuckhoffet al. 197/175 ux [54] PLASTIC RIBBON SPOOL 5 Claims, 10 Drawing Figs.

[52] U.S.Cl..... [5| Int. Cl B65h 75/28 Primary Examiner-George F. Mautz Assistant Examiner-Gregory A. Walters Attorney Kevin C. McMahon ABSTRACT: Plastic ribbon spools in which a tab folduble from a spool flange, is adapted to pinch and secure one end of an inked ribbon to the spool core and lock in place with the ribbon so secured.

PATENTEU 231971 3.622.099

SHEET 1 0F 3 INVENTOR Y JOHN W H B\sHoP y AM /M HTTORI'JEI PATENTEDN 23 I97\ 3 622 O99 sum 2 or 3 \NVENTOR BY JOHN W H. B\$HOP MWM RTTORNEV PLASTIC RIBBON SPOOL BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to plastic ribbon spools used for carrying inked ribbons for typewriters, adding machines and the like. More particularly the invention relates to such spools to which a ribbon must be positively secured to permit the winding and unwinding a plurality of times of a reusable ribbon.

2. Description of the Prior Art Metal ribbon spools usually must be stamped out in pieces which must then be assembled. Plastic ribbon spools can be molded in one piece and are accordingly less expensive. It is now quite common to utilize nonreusable inked plastic ribbon for typewriters. Since the plastic ribbon and spool are normally discarded after one pass, the method of attaching the two is of little consequence. Sometimes a little adhesive is applied or a small piece of adhesive tape. It is also possible to wind the ribbon with the inner end secured only by the next turn of ribbon.

A different problem is presented with reusable ribbons. In automatic machines, in adding or calculating machines having printout, and in portable typewriters, reusable fabric ribbons of silk or nylon are more common. These ribbons are commonly secured to the spools by spear prongs mounted on the spool core. Other methods usually require a separate attaching clip or an extra operation with the ribbon such as fastening a hook to the ribbon, forming a loop in the ribbon, or securing an eyelet in the ribbon.

It would seem apparent that the spear prong approach is the simplest. However, spear prongs formed from plastic in a onepiece plastic spool are neither sharp nor sturdy. Aggravating this problem is the trend toward nylon ribbon fabric which is quite difficult to pierce. Thus there is a continued use of metal spools for fabric ribbons and use of an extra operation with the ribbon when plastic spools are used.

SUMMARY OF THE INVENTION In accordance with the present invention a plastic ribbon spool is formed in a single piece provided with a tab for securing a fabric ribbon positively in place. The tab is formed in one of the spool flanges permanently connected near the spool core, but foldable out of the flange and down across the hub to lock in a mating recess integral with the opposite flange. In manufacture, a ribbon end is drawn against the spool hub, a mechanical finger is applied against the tab, folding it down across the ribbon so that it locks in said recess and then the ribbon is wound on the spool as required. Thus it is an object of the invention to provide a novel plastic ribbon spool with integral means for positively securing a fabric ribbon thereto.

It is a further object of the invention to provide a plastic ribbon spool provided with an integral tab foldable across a ribbon and lockable in place so as to secure such ribbons.

It is a further object of the invention to define a method for securing a ribbon to a plastic spool having integral securing means by simple mechanical motions.

These and further objects of the invention will be more clearly understood upon reading the following description together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of a ribbon spool according to one embodiment of the invention.

FIG. 2 is a cross section through 2-2 of FIG. I.

FIG. 3 is a perspective view of a ribbon spool with one tab folded according to a second embodiment of the invention.

FIG. 4 is a cross section of a portion of the spool of FIG. 3 through 4-4 showing the tab-latching arrangement.

FIG. 5 is a plan view of a ribbon spool according to a third embodiment of the invention.

FIGS. 6 and 7 are top and bottom views of a ribbon spool according to a fourth embodiment of the invention.

FIG. 8 is a partial section of a ribbon spool showing a'tablatching arrangement according to a fifth embodiment of the invention.

FIG. 9 is a partial cross section of a ribbon spool showing a tab-latching arrangement according to a sixth embodiment of the invention.

FIG. 10 is a partial cross section of a ribbon spool showing a tab-latching arrangement according to a seventh embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As depicted in FIGS. I and 2, a ribbon spool for inked ribbons normally:comprises core 10, top flange 11 and bottom flange 12. The core is formed of inner portion 14 designed to mate with a spindle for rotatably supporting the spool and an outer portion of hub 15 upon which ribbon can be reeled. Inner portion 14 commonly includes keyway 16 or similar means to interlock the spool with a spindle.

In the spool of FIG. 1, top flange 11 is discontinuous at two positions 17, 18 displaced around hub 10. Flange 11 is molded of plastic leaving tabs 20 and 21 at the discontinuous positions 17 and 18 respectively. As depicted, tabs 20 and 21 are generally rectangular and are connected to hub 15 at flange 11 by two legs 24, 25. Two or more legs are used rather than a solid continuous connection since it reduces the tendency to fracture upon folding. Narrow tongues 26 extend from the outer ends of each tab 20, 21 to engage latching recess 27 in bottom flange 12. The narrowness of tongue 26 enables a smaller latching arrangement so as to facilitate latching.

Each tab 26 has a plurality of apertures 28 for engaging projections 30 from hub 15. Projections 30 can just as easily be formed integral with tabs 20, 21 whereupon the latching recesses would be in hub 15. It is preferable, although not essential, that one of projections 30 be centrally located between flanges 11 and 12. This permits the use of a ribbon having an eyelet that would then be secured on the central projection.

Bottom flange 12 has narrow recesses 27 adjoining core 10 underlying the connected portion of each of the tabs 20, 2]. Portions of core 10 are also recessed adjacent to recesses 27. Latching fingers 31 are formed in flange 12 adjacent to recesses 27. Fingers 31 are about the width of tongues 26 and have slits 33 on either side permitting them to be depressed without stressing flange 12.

The flexiblity of fingers 31 can be enhanced by thinning out flange 12 at fingers 31 as depicted in FIG. 2. Thickened lips 32 can be formed at the end of fingers 31 for increasing the latching effect of the fingers. Tabs 20, 21 can as readily be in bottom flange 12 and latching recesses 27 in top flange 11.

Preferably slight indentation 34 is fonned in the connected ends of tabs 20, 21 to facilitate folding and reduce the probability of fracture.

While the length of tabs 20, 21 extending from core 10 to their outer ends is depicted in FIGS. 1 and 2 as the distance between core 10 and the periphery of flange II, this is not significant. In the embodiment of FIGS. I and 2 the criticality is that shoulders 35 adjacent to tongues 26 of tabs 20, 21 do not bind against flange 12 when tabs 20, 21 are folded. Nonbinding contact of shoulders 35 against flange 12 is permissible and can even be desirable since it provides stabilizing support for the tabs 20, 21 in the folded positions.

The length of tongues 26 extending beyond shoulders 35 must be sufficient for secure latching action and is preferably at least as long as the thickness of flange 12. Greater length is permissible where the projection beyond flange 12 will not interfere with the operation of the spool in a particular machine. The overall length of tabs 20,21 including tongues 26 is determined by the spacing between flanges 11 and 12. The length must be somewhat greater than the spacing between flanges II, 12 so that latching action can be provided.

In order to avoid an undue hump on the winding surface of the spool core when the tab is folded, the core can be "flatted or recessed to accept the tab.

In FIG. 3, the spool core 40 has a flatted portion 41 for receiving tab 42. Guide path 44 is also provided in flange 45 for guiding tongue 26 into recess 27 (see FIG. 4). Guide path 44 is preferably molded into flange 45 so as to provide two raised ridges 46 that are substantially farther apart than the width of tongue 26 toward the periphery of flange 45 and taper together to approximately the same width as tongue 26 at recess 27. This insures that tab 42 will always be guided to latching recess 27 even though it bends slightly out of alignment on folding.

As depicted in FIG. 4, tab 42 has thickened or projecting area 47 over a portion of its inner surface that mates with recess 48 of core 40. Projecting area 47 can comprise a substantial portion, for example, two-thirds of the inner surface of tab 42. With core 40 in the form of a hollow cylinder, recess 48 can be an aperture in the wall of the cylinder. Slight beveling of the end of tongue 26 as depicted in FIG. 4 has been found to provide smoother latching action.

As previously mentioned, there is no necessary relation between the diameter of the spool flange and the length of the tabs. In FIG. 5, flange S1 is depicted comprising solid periphery 52 and tab 20 extending from core 50 to a point near solid periphery 52. When tab 20 is shorter than the width of flange 51 due to a flange width relatively large compared to the flange spacing, a solid peripheral edge of flange 51 insures better guidance of the ribbon when reeled.

A foldable tab can just as readily be formed in the bottom flange as the top. Thus in FIGS. 6 and 7 tab 63 is in bottom flange 62 of the spool. Tab 63 is formed without a tongue and latching action takes place at its edges rather than at its end. The latching aperture is illustrated in FIG. 7 by opening 65 in flange 61 terminating in latching recess 66. Opening 65 is wide near periphery 67 of flange 61 and tapers to a more narrow width than the width of tab 63. At the most narrow point, two shoulders 68 are followed by latching recess 66 of substantially the same width as tab 63. As in the case of the previous embodiments, it is preferable to have a recess or aperture in core 60 adjacent to latching recess 66 whereby tab 63 can be depressed slightly beyond latching recess 66 to insure clearance of shoulders 68.

Since only one tab 63 is normally utilized, additional tabs provided for convenience can be partially attached by a frangible connection (not shown) to peripheral portion 67 of flange 61.

FIGS. 8, 9, and utilize a variation of the latching arrangement in which a segment of the core wall is used. This latching arrangement is called herein the barb lock.

In FIG. 8, tab 74 has projecting portion 75 for engaging aperture 76 in core 70 and barb 77 for locking onto edge 78 at the opposite end ofcore 70. Flange 71 opposite the flange carrying tab 74 has an aperture 79 for permitting passage of barb 77. Barb 77 is a latching hook formed in the end of tab 74 which bends back upon being pressed against edge 78 until it ships over the edge locking on. Barb 77 also provides an easy means of fingertip release when necessary.

FIGS. 9 and 10 depict embodiments similar to the embodiment of FIG. 8 in which the barb is fonned on the core of the spool instead of the tab. In FIG. 9, core 80 carries top and bottom flanges 81 and 82 with tab 84 formed in flange 82. Barb 85 projects outwardly from the top end of core 80 with its outer end above the surface of flange 81 to facilitate fingertip release action. Barb 85 has shoulder 86 and recess 87 for catching and securing end 88 of tab 84.

In the embodiment of FIG. 10 barb 95 formed from core 90 has its outer end flush with the surface of flange 81. FIG. 10 depicts a projecting surface area 91 on tab 94 for mating with aperture 92 in the hub of core 90. FIG. 9 depicts apertures 96 in tab 84 for mating with projecting knubs 97 of core 80. Multiple interlocking knubs, interlocking serrations or splines can also be utilized for gripping a ribbon between tab and core.

Iclaim: 1. A ribbon spool for inked ribbons used in impact printing comprising:

a. A core having a first and a second end;

b. A first flange secured to said first end perpendicular to said core;

c. A second flange secured to said second end parallel to said first flange;

d. A foldable tab integral with said first flange and foldable adjacently across said core between said first flange and said second flange;

e. A slot in said second flange proximate said core and directly opposite said tab for receiving the end portion of said tab for latching said tab in the folded position, the portion ofsaid second flange proximate said slot and radially outward therefrom having a smaller thickness than the rest of said second flange for allowing flexure of said second flange proximate said slot under the camming pressure of said tab during folding; and

f. guide means in said second flange for guiding the end portion of said tab toward said slot during folding.

2. A ribbon spool according to claim I wherein said ribbon spool is an integral plastic molding.

3. A ribbon spool according to claim 1 wherein a portion of said tab has a projecting area projecting beyond the surface of said first flange in the direction of said second flange and said core has a mating recess for receiving said projecting area when said tab is folded thereby pinching a ribbon therebetween into said recess.

4. The ribbon spool of claim I further including an inwardly extending thickened lip portion in said second flange along the radially outward edge of said slot for assisting in latching action ofsaid slot.

5. The ribbon spool of claim 1 wherein said guide means includes a slit extending approximately radially outward from each end of said slot for increasing the flexibility of said second flange proximate said slot. 

1. A ribbon spool for inked ribbons used in impact printing comprising: a. A core having a first and a second end; b. A first flange secured to said first end perpendicular to said core; c. A second flange secured to said second end parallel to said first flange; d. A foldable tab integral with said first flange and foldable adjacently across said core between said first flange and said second flange; e. A slot in said second flange proximate said core and directly opposite said tab for receiving the end portion of said tab for latching said tab in the folded position, the portion of said second flange proximate said slot and radially outward therefrom having a smaller thickness than the rest of said second flange for allowing flexure of said second flange proximate said slot under the camming pressure of said tab during folding; and f. guide means in said second flange for guiding the end portion of said tab toward said slot during folding.
 2. A ribbon spool according to claim 1 wherein said ribbon spool is an integral plastic molding.
 3. A ribbon spool according to claim 1 wherein a portion of said tab has a projecting area projecting beyond the surface of said first flange in the direction of said second flange and said core has a mating recess for receiving said projecting area when said tab is folded thereby pinching a ribbon therebetween into said recess.
 4. The ribbon spool of claim 1 further including an inwardly extending thickened lip portion in said second flange along the radially outward edge of said slot for assisting in the latching action of said slot.
 5. The ribbon spool of claim 1 wherein said guide means includes a slit extending approximately radially outward from each end of said slot for increasing the flexibility of said second flange proximate said slot. 